Amphoteric starch

ABSTRACT

Amphoteric starch which contains both basic (e.g., tertiary amino or cyanamide) and acidic (e.g., sulfonic or carboxylic) groups linked to the starch molecule and which is especially useful for sizing mixed fibers in the form of threads or yarns, such as mixtures of polyester fibers and cotton fibers. The products also have other advantages. For example, they can be dyed with both acid and basic dyes.

United States Patent LeelLElizer Inventor Keokuk,1owa Appl. No. 816,100 Filed Apr. 14, 1969 Patented Nov. 23, 1971 Assignee The Hubinger Company Keokuk,1owa Continuation-impart of application Ser. No. 597,561, Nov. 29, 1966, now abandoned. This application Apr. 14, 1969, Ser-No. 816,100

AMPHOTERIC STARCI-l 15 Claims, No Drawings US. Cl......' 260/233.3 R, 106/210, 106/212, 106/213, 1 l7/139.5C Int. Cl. C08b 19/01 Field of Search 260/2333;

' Primary Examiner-Donald E. Czaja Assistant Examiner-M. l. Marquis Attorney-Johnston, Root, OKeeffe, Keil, Thompson and Shurtlefi' ABSTRACT: Amphoteric starch which contains both basic (e.g., tertiary amino or cyanamide) and acidic (e.g., sulfonic or carboxylic) groups linked to the starch molecule and which is especially useful for sizing mixed fibers in the fonn of threads or yarns, such as mixtures of polyester fibers and cotton fibers. The products also have other advantages. For example, they can be dyed with both acid and basic dyes.

fibers and for a wide variety of other industrial purposes. In 5 recent years many synthetic fibers have become available and it has been difficult to find relatively inexpensive sizing compositions which are suitable for sizing a wide variety of these fibers, including mixtures of cotton and synthetic fibers. In

particular, it has been difficult to provide suitable low cost sizing compositions for mixtures of polyester fibers (e.g., Dacron) and cotton. In common practice, the fibers are sized in the form of threads or yarns prior to weaving. The sized threads or yarns are then woven into cloth and thereafterthe sizing material is removed by washing with water containing detergent or by treatment with enzymes. A satisfactory sizing composition is one which will provide suitable lubrication and resistance during weaving and at the same time can be readily removed thereafter.

One of the objects of the present invention is to provide new and improved starch products which are especially useful in textile sizing and can be employed for a wide variety of other purposes. Other objects will appear hereinafter.

In accordance with the invention, a starch is prepared .in the form of ungelatinized starch granules which contain both cationic and anionic groups. These new and improved starch products are prepared by reacting ungelatinized starch with a nitrogen-containing etherifying agent to introduce a'cationic group into the starch molecule, for example, one containing a tertiary amino and/or a cyanamide radical, and also with a reagent capable of introducing an anionic group into the starch molecule, for example, one containing a sulfonic or carboxylic radical.

Preferred nitrogen-containing etherifying agents are 2- chlorethyldiethylamine hydrochloride, also called 2- chlorotriethylamine hydrochloride, and 4-chloro-2-butenyltrimethyl ammonium chloride having formulas l and ll, respectively, as follows:

Preferred reagents for introducing anionic groups into the starch molecule are propane sultone and sodium chloroacetate having formulas ill and IV, respectively, as follows:

III. HtC-CH2 The reaction with the ungelatinized starch can be carried out either sequentially or simultaneously. Thus, the 2- chloroethyl diethylamine hydrochloride or 4-chloro-2-butenyltrimethyl ammonium chloride can be reacted with the starch first, followed by the addition of the propane sultone or sodium chloroacetate, or the propane sultone orsodium chloroacetate can be reacted with the starch, followed by the addition of the Z-chlorotriethylamine hydrochloride, or 4- chloro-Z-butenyltrimethyl ammonium chloride, or the 2- chloroethyldiethylamine hydrochloride and/or 4-chloro2-butenyl trimethyl ammonium chloride and the propane sultone and/or sodium chloroacetate can be mixed together in water to form a clear solution .before stirring the mixture with a starch slurry.

The basic amino groups are preferably introduced into the starch molecule by using as one of the reactants a tertiary amine or amine salt containing a reactive group linked to a hydrocarbon group of the amine. The hydrocarbon group or groups of the amine can be alkyl (e.g., methyl, ethyl, propyl,

isopropyl, butyl, isobutyl), aryl (e.g., phenyl, tolyl), aralkyl (e.g., benzyl), or cycloalkphatic (e.g., cyclopentyl, cyclohexyl, or cycloheptyl). The amine can be a monoamine or a polyamine but is preferably a monoamine. It can also be a heterocyclic amine (e,g., piperidine, pyridine). ln general, however, from the standpoint ofease of carrying-out the reaction and of desirable properties in the resultant products, it is preferred to use .a water soluble amine. The reactive groups of the amine are preferably either halogen (e.g., chloro-, bromo-, etc.).or epoxy. The portion of the amine to which the reactive group is attached is acyclic. The reactive group is preferably separated from a nitrogen atom of-the amine by at least one carbon atom, usually two to six carbon atoms.

The resultant products any be described by the following structural formula:

wherein X is starch, An isananionic group, e.g., carboxylic, carboxylate, .sulfonic, sulfonate, phosphate, .phosphonate, or other anionic group, Cat-is'cationic'group, e.g., tertiary amino, or quaternary, or other amine or amine salt, R and R are divalent acyclic hydrocarbon or hydroxyhydrocarbon groups having'one to six carbon atoms, .and m and n represent the number of times these radicals occur, usually a minimum of 0.5 each per 100 anhydroglucose units and a total of m+n not exceeding 16.

A preferred group of products is represented by the following general fonnula:

VI. a

where X is starch, R and R are divalent acyclic hydrocarbon or hydroxyhydrocarbon groups preferably having one to six carbon atoms and morespecifically one to four carbon atoms; R and R are hydrocarbon, preferably alkyl having one to six carbon atoms and more specifically one to four carbon atoms;

Y is hydrogen or a salt forming radical, e.g., sodium, potassium, calcium, ammonium, and m and n are numerical values representing the number of times :the anionic and cationic The term starch whenus edhereih refers to un g e latinized starch which can be natural starch or a modified starch containing reactive hydroxyl groups. Among the modified starches which are useful are thin boiling starches prepared by slurrying corn starch in water acidified to 0.] N with HCl for 10 to hours at temperatures below gelatinization temperatures. High amylose starches can also be used. The starch can be of any origin, for example, corn, wheat, potato, waxy corn, tapioca, sago or rice.

Sultones are intramolecular cyclic esters of hydroxysulfonic acids and may be derived both from aliphatic and from aromatic sulfonic acids. Examples of sultones suitable for the present purpose are l,3-propanesultone, l,4-butanesultone, mixtures of isomeric butanesultones (which may be prepared from mixtures of chlorobutanesulfonic" acids, obtained by sulfochlorination of l-chlorobutane), benzylsultone and tolylsultone.

Sodium chloroacetate is the sodium salt of monochloroacetic acid. The free acid can be used but since the reaction is carried out under alkaline conditions it will be convened to a salt. Other reactive halogen aliphatic acids and their salts (e.g., Na, K, Ca) containing two to six carbon atoms can be used, for example, monobromoacetic acid and its sodium salt, and monochloropropionic acid and its salts.

Examples of amine etherifying agents suitable for the practice of the invention are: 2-chloroethyldiethylamine; 2- chloroethyldiethylamine hydrochloride; 2-chloroethyldimethylamine; 2-chloroethyldimethylamine hydrochloride; 3-chloropropyldiethylamine; 3-chloropropyldiethylamine hydrochloride; 3-chloropropyldimethylamine; 3-chloropropyldimethylamine hydrochloride; 4-chlorobutyldiethylamine;

4-chlorobutyldiethylamine hydrochloride; 2-chloroisopropyldimethylamine; 2-hydroxy-3-chloropropyltrimethylamine chloride; 3-dibutylamino-l,2-epoxypropane; 2-bromo-5- diethylaminopentane hydrobromide; N-(2,3-epoxypropyl) piperidine, and N,N-(2,3-epoxypropyl)methyl aniline. In general, it is preferable to use the salts of the amine esterifying agents, such as, for example, the hydrochlorides and the hydrobromides. Mixtures of amine etherifying agents can be employed. The salts should be selected so as to avoid formation of precipitates. For example, if calcium, strontium or barium is present, sulfates or phosphates should not be used because insoluble salts such as calcium sulfate or calcium phosphate would form. However, sulfates or phosphates can be used where sodium, potassium or lithium ions are present.

The reagents for introducing anionic and cationic groups both act as etherifying agents for starch under basic conditions. The reaction can be carried out at ordinary or slightly elevated temperatures below the temperature at which the starch gelatinizes, for example, within the range of 35 F. to 130 F. In order to obtain uniform reaction, it is desirable to mix the reactants with a solvent, preferably water. Other solvents canbe used but they are more expensive and in some cases present problems in recovering the product. The product is insoluble in water and therefore can be recovered by filtration, washing with water and drying.

The invention will be further illustrated but is not limited by the following examples in which the quantities are stated in parts by weight unless otherwise indicated.

EXAMPLE] A slurry of 5,000 grams of No. 50 thin boiling regular corn starch in 5 liters of water was prepared. A slurry of l68 grams I hydrochloric acid. The resultant product was then divided into 2 equal portions. The first portion was filtered, reslurried with water to 5 liters, filtered again, reslurried with water to 5 liters, filtered a third time, reslun-ied with water to 5 liters, filtered again and dried.

The second-portion was adjusted to a pH of 1.0 by adding 6N hydrochloric acid and a dry product was recovered in the same manner as for the first portion. l00 grams of the second portion was slurried in distilled water and diluted to one liter. After 5 minutes the pH was 4.0. Then I00 cc. of slurry was removed, filtered, air dried and labeled. The pH was adjusted to 5.0 with saturated sodium carbonate solution. After 5 minutes 100 cc. of this slurry was removed, filtered, air dried and labeled. The above process was continued in steps of 0.5 pH unit to pH 10.5. A portion of each product was slurried in 2 different solutions, one solution being a 0.000l molar aqueous solution of Light Green SF yellowish dye (Color Index No. 42095 and the other solution containing the same amount of Methylene Blue basic dye (Color lndex No. 52015).

The granules of the product accepted the acid dye (Cl No. 42095) from pH 4.0 through pH 6.0. No dyeing took place at pH 7. The granules also accepted the basic dye from pH 10.5 through 7.0. They did not dye at pH 6. It is therefore believed that the isoelectric point must be between 6 and 7.

The foregoing products contained about three propyl sulfonic acid groups per 100 anhydroglucose units and about 3.7 basic amino groups per 100 anhydroglucose units.

An aqueous paste of these products prepared at the isoelectric point was effective in sizing a multifiber test fabric containing cellulose acetate, Acrilan I656, Arnel, cotton, Creslan 6l, Dacron 54, Dacron 64, nylon 66, Orlon 75, silk, Venel A,

A slurry was prepared consisting of 5000 grams of dry No. 50 thin boiling regular corn starch in 5 liters of water. 56 grams of calcium oxide diluted to one liter with water was poured into the starch slurry and the whole mixture diluted with water to l0 liters. This mixture has a pH of l 1.5 at 82 F. 61.1 grams of propane sultone was added to the starch slurry and reacted at 82 F. for 4 hours. 86 grams of 2-chloroethyldiethylamine hydrochloride in one liter of water at F. was stirred into the slurry and the resultant mixture was reacted at 78 F. for 18 hours. It was divided into two equal portions.

in the first portion the pH was adjusted to 1.0 with 6N hydrochloric acid at a temperature of 80 F. The slurry was filtered, the residue reslurried in 5 liters of water, filtered, reslurried again in 5 liters of water, filtered, reslurried again in 5 liters of water, filtered anddried.

The second portion of the slurry was adjustedto pH 7.0 with 6N hydrochloric acid at a temperature of 80 F. and a dry product was recovered in the same manner as with the first portion.

Both products contained about l.7 basic amino groups per anhydroglucose units. Both products also contained approximately one propyl sulfonic acid group per I00 anhydroglucose units.

Samples of these products adjusted to various pHs were dyed with an acid dye light green SF yellowish (CI 42095) and also with a basic dye Methylene Blue (Cl 52015). The products accepted the acid dye at a pH of 1 to 4 and the basic dye at a pH of 6.5 to 10. The isoelectric point was therefore determined to be between pH 4 and 6.5.

in examples I and H the number 50 thin boiling regular corn starch is prepared in a conventional manner by mixig 60,000 pounds of dry corn starch in a 20 Be. slurry with hydrochloric acid to make about a 0.1 N solution. The temperature is adjusted to 125 F. and the mixture is allowed to undergo reaction at this temperature until the No. 50 fluidity point is reached. To determine this point, 5 grams of dry starch slurried in water is neutralized and washed and slurried in 90 cc. of 0.1 N sodium hydroxide. After a predetermined time, under refrigeration, the mixture is poured through a standard funnel. The fluidity is the number of cc. that passes through the funnel in 1 minute. For unmodified starch only one cc. can be collected in 1 minute. For No. 50 thin boiling starch 50 cc. can be collected in 1 minute.

EXAMPLE 111 5000 grams of No. 50 thin boiling regular corn starch containing 30.8 AGU was slurried in 5 liters of water and then diluted to liters at the ambient temperature of 80 F. 2 liters of the slurry were removed and allowed to stand for 23 hours at an ambient temperature of 74 F. The pH was determined to be 5.5. It was adjusted to 7 by adding 0.1 N sodium hydroxide. The starch was then filtered, reslurried in 2 liters of water, filtered, reslurried again in 2 liters of water, filtered, reslurried in 1 liter of distilled water, filtered and dried. This product was labeled 37.1-26.

90 grams of calcium oxide was slurried in200 cc. of water diluted to 400 cc. and stirred into the remainder of the original starch slurry. 2100 cc. of this product was removed and allowed to stand for 23 hours at 86 F. It was determined to have a pH of 11.8. The pH was adjusted to 7.0 by adding 6 N hydrochloric acid. The product was then filtered, reslurried in 2 liters of water, filtered, reslurried again in 2 liters of water, filtered, reslurried in 1 liter of distilled water, filtered and dried. This product was labeled 37.2-26.

To 2100 cc. of the original starch slurry, 34.4 grams of 2- chloroethyldiethylarnine hydrochloride was added and the mixture reacted 22 hours at 84 F. The pH was detennined to be 1 1.3 at 74 F. at the end of this period. This was adjusted to pH 7.0 by adding 6.0 N hydrochloric acid and the product was recovered in the same manner as with 37.1-26 and 37.2-26. This product was labeled 37.3-26.

To the remaining 4200 cc. of the original slurry, 48.9 grams of propane sultone was added and the reaction was allowed to proceed for 4 hours at 80 83 F. 2100 cc. of the resultant product was removed and allowed to stand for 18 hours at 75 F. The pH was determined to be 1 1.6. The pH was adjusted to 7.0 by adding 6N hydrochloric acid and a dry product was recovered as described in 37. 1-26 and 37.2-26. The resultant product was labeled 37.4-26.

To the remaining 2100 cc. of starch slurry reacted with propane sultone there was added 34.4 grams of 2-chloroethyldiethylamine hydrochloride dissolved in 100 cc. of water and this mixture was allowed to stand at 78 F. for 17 hours. The pH was determined to be 1 1 at 74 F. and was adjusted to 7.0 by the addition of 6N hydrochloric acid. This product was labeled 37.5-26.

The following evaluation of these products was then made:

TABLE 1 In table 1, the Scott 0.35 AGU/SO/sec. entry is a standard viscosity determination. The first entry is the grams of the respective starch product needed to give 0.35 AGU, the second entry indicates the volume in cc. of the starch product used in the viscosity determination, the third entry is the number of seconds required for flow of the 50 cc. of starch product under the Scott viscosity determination. The S/100 AGU indicates moles of sulfur per 100 anhydroglucose units.

The first four columns of the table refer to products that are outside of the scope of the invention. Only the fifth column covers a product within the scope of the invention. It will be noted particularly that only in the fifih column was the cold Scott paste fluid. In the others, the products formed a softgel or a stiff gel. This is an important factor in the utility of the products.

120 grams of product 37.5-26 was slurried in 1,200 ml.

- distilled water. The pH was adjusted to 7.0 by adding 6N hydrochloric acid and the slurry was divided into two equal portions, A and B. 100 cc. of A was filtered and air dried and labeled 37.5A-7.0. The pH of the remainder of A was adjusted to 6.5 with 6N hydrochloric acid. 100 cc. was filtered, air dried and labeled 37.5A-6.5. Similarly, other 100 cc. portions of A were prepared, each having a pH decreasing by 0.5 pH unit.

The portion B was divided into parts each consisting of 100 cc. and a sufficient amount of 10 percent potassium hydroxide was added to raise the pH by steps of 0.5 unit. ln each case the slurry was filtered and dried.

Portions of each product were then slurried with 0.001 N acid dye CI 42095 and basic dye CI 52015. The isoelectric point appeared to be at a pH of 6.0. Below 6.0 no dyeing occurred with the basic dye but dyeing did occur with the acid dye, and above 6.0 no dyeing occurred with the acid dye but it did occur with the basic dye.

1n the foregoing example, the product 37.5-26 contains about two sulfur atoms per 100 AGU and three nitrogen atoms per 100 AGU which means that there are two acidic groups for every three amino groups.

EXAMPLE IV 5000 grams of dry No. 50 thin boiling regular corn starch (30.8 AGU) was slurried in 5 liters of water. To this was added 1 12 grams of calcium oxide in 1 liter of water. The resultant slurry was stirred and diluted with water to 1 1 liters. At F. it had a pH of 1 1 .9. It was divided into five equal portions each containing 1000 grams of starch (6.16 AGU) and 0.4 mole of calcium oxide.

To part one was added 24.4 grams (0.2 mole) propane sultone and after 4 hours at 72-74 F. there was added 0.2 mole of Z-chloroethyldiethylarnine hydrochloride in 100 cc. of water. The mixture was stirred and allowed to stand 18.5 hours at about 75 F. The pH was adjusted to 7.0 with 6N hydrochloric acid. After 15 minutes the product was filtered, reslurried in 2 liters of water, filtered again, reslurried in 2 liters of water, filtered, reslurried in 1 liter of distilled water, filtered again and dried. This product was labeled 19.1.

The process used in preparing product 19.1 was repeated except that 0.16 mole (19.5 grams) of propane sultone was employed. This product was labeled 19.2.

The process used in preparing product 19.1 was repeated except that 0.12 mole of propane sultone was employed 14.65 grams). This product was labeled 19.3.

Oven dry solids, percent Ash, percent dry b Nitr en, percent dry basis 0.05 Scott .37 AGU/fiO/sec 63 tt paste, p 7 3 N/ AGU- 5' Cold Scott paste Sulfur percent dry basis 8/100 AGU The process used in product 19.1 was repeated except that 0.08 mole of propane sultone was employed (9.75 grams). This product was labeled 19.4.

The process used in preparing product 19.1 was repeated served that the isoelectric pl-l goes down as the basic groups decrease.

EXAMPLE V1 except that 0.04 mole of propane sultone was used (4.88

product was labeled 19.5. The process was carried out as in examples 1V and V except An evaluation of these products is given in table 2. that the reaction time between the starch and the propane sul- TABLE 2 Oven dry solids, percent 84. 06 79. 59 88. 66 89. 53 91. 36 Ash, percent dry basis 0. 24 0. 0. 99 0. 09 0. 10 Nitrogen, percent dry basis,

N/100AGU 0. 24-2. 3 0. 24-2. 3 0. 25-2. 4 0. 22-2. 1 0. 27-2. 6 Suliur, percent dry basis,

8 100AGU 33-2. 8 0. 27-2. 3 0. 14-1. 2 0. 10-0. 9 0. 06-0. 5 Scott 0.35 AGU/50/sec- 67 5/50/40 71. 2/50/38 64. 0/50/43 63. 3/50/48 62. 1/50/48 Cold Scott pasta... Fluid Soft Stlfl Stifl Stifl Cold Scott pH. 7. 1 7. 2 7.0 7. 2 6.8 Isoelectrlc pH range 5. 0-7. 0 6. 0-8. 0 8. 0-10. 0 8. 5-10. 5 10. 0

the viscosity of the Scott cold paste increases as the number of acidic groups decreases. Also, the isoelectric pH range increases as the number of acidic groups decreases.

The various products prepared as above described were adjusted in pH and the viscosity and cold paste characteristics were observed. The product 19.1 at pHs 4 to 8 remained fluid. The product 19.2 at pHs 5 to 9 remained fluid. The product 19.3 at pHs from 7 to 1 remained fluid. The product 19.4 at pH's from 7.5 to 11 formed a soft gel. The product 19.5 at pH's from 8 to 1 1 formed a medium gel. Thus, a fluid product was obtained from a ratio of acidic to basic groups from about 0.5:1 to more than 1:1.

EXAMPLE V The same procedure was used as in example IV except that the relative proportion of propane sultone was kept constant and the amount of 2-chloroethyldiethylamine hydrochloride was varied. 5 products were prepared which were labeled 18.1, 18.2,18.3, 18.4and 18.5.

The evaluation of these products is shown in table 3.

tone but before the addition of the amine was omitted. It was found that this reaction time was unnecessary. A higher sulfur content resulted when the two reactants were added at about the same time.

EXAMPLE V11 5,000 grams of regular corn starch (30.8 AGU) was slurried in 6 liters of water to which had previously been added 168 grams of calcium oxide. The slurry was diluted to 10 liters with water. One-fifth of the slurry was then mixed with 51.6 grams (0.3 mole) of 2-chloroethyldiethy1amine hydrochloride which had previously been dissolved in 0.6 mole of water, together with 0.3 mole of propane sultone at 86 F. The amine hydrochloride and the propane sultone fonned a clear solution in water which was stirred into the starch slurry at about 69 F. The mixture was then reacted for 18 hours at a temperature of about 80 F. At this point the slurry had a pH of l 1.0. The pH was then adjusted to 7.0 by adding 1.0 N hydrochloric acid. The product was filtered, reslurried in 2 liters of water, filtered, reslurried in 2 liters of water, filtered, reslurried in 1 liter of distilled water, filtered and dried. This product had an isoelectric pH range from 6.0 to 7.5. It contained 3.9 nitrogen atoms per 100 AGU and 1.9 sulfur atoms per 100 AGU. The cold Scott paste was fluid.

EXAMPLE V111 This example relates to a different kind of amphoteric starch from the products described in examples 1 to V11 in that TABLE 8 Oven dry solids, percent 87. 73 85. 46 90. 09 88. 43 91. 31 Ash, percent dry basis 0. 25 0. 30 0. 42 0. s3 0. 62 Nitrogen, percent basis. 0. 27 0.22 0.17 0.136 0.08 suitor percent dry asts 0.26 0. 25 0. 25 0.27 0. 25 Scott .35 AGU//sec- 64. 6/50/40 66. 3/50/37 62. 9/50/38 64. 1/50/35 62.1/50/37 Scott gcaste, H 7. 0 7. 5 7.3 7. 7 7. 0 Cold ott paste Fluid E1 1d Soft sort Stlfl Isoelctrlc pH range 5. 5-7. 6 4. 0-6. 0 2. 0-3. 0 1. 5-2. 5 1. 0-2. 0 Su11ur/100AG 2.3 2.1 2.2 2.3 2.2 Nitrogen/100 AGU 2 7 2. 1 1. 8 1. 4 0. 93

It will be noted that the ratio of acidic groups to basic the basic groups are introduced by adding a cyanamide comgroups in these products varies from slightly less than 1:1 to 65 pound. more than 2:1. Products 18.1 and 18.2 formed fluid cold 5000 grams of No. 50 thin boiling regular corn starch (30.8 p AGU) was slurried in 5 liters of water and diluted with water Samples of modifications of these products were prepared to 10000 cc. After 500 cc. of the slurry had been removed, the y jus ing 1110 P and i was found h Product 181 had a remainder of the slurry was reacted with 6107 grams (0.5 fluid cold paste at a pH of 5.1 to 7.6. Product 18.2 had a fluid mole) of propane sultone at 8292 F. for 4 hours. 250 cc. of

cold pmte at a pH of4.4 to 6.5. Product 18.3 had fluid cold paste at a pH of 3.1 to 5.0. Product 18.4 had a fluid cold paste at a pH of 3.6 and 4.7. Product 18.5 had a fluid cold paste at a pH of 3.1 and 4.5. The viscosity at the isoelectric pH was this slurry was removed and the remainder was reacted with 400 cc. (210 grams, 5 moles) of a 50 percent solution of hydrogen cyanamide (H,NCN) in water for 17 hours at 76-78 F. The pH was adjusted to 1.0 with 6N hydrochloric higher that above or below pH. It was obacid, and the product was filtered and reslurried with 10 liters of water three times. Thereafter, 50 grams of aluminum sulfate in 100 cc. of water was stirred into the slurry and the slurry was divided into five equal parts. The first part, labeled 44.1, was filtered and dried. The second part, labeled 44.1, was adjusted to a pH of 3.0 and filtered and dried. The third part was labeled 44.3, was adjusted to a pH of 3.6 and filtered and dried. The fourth part, labeled 44.4, was adjusted to a pH of 4.5, filtered and dried. The fifth part, labeled 44.5, was adjusted to a pH of and filtered and dried. The fifth part was found to be very viscous. The other four parts all gave fluid cold Scott paste. Controls prepared without the addition of the sultone and the cyanamide all gave cold Scott pastes which were stiff gels.

The products 44.1, 44.2, 44.3, 44.4 were all suitable in sizing textile fibers in the manner previously described. These products all contained about 0.9 percent nitrogen as compared with 0.04 to 0.06 percent nitrogen in the original starch. The products also contained sulfur in the fonn of sulfonic acid groups.

EXAMPLE IX 5000 grams regular corn starch was slurried in eight liters of water and diluted to 12 liters with water. 75 grams of Ca(OH), in one liter of water was added to the starch slurry. Then 75 grams of Z-chloroethyldiethylamine hydrochloride dissolved in 100 cc. of water was stirred into the slurry. Thereafter, 25 grams of sodium chloroacetate in 100 cc. of water was stirred into the slurry. The mixture was held at a temperature of l-l24 F. for 16 hours. The pH at the end of this period was l 1.1. it was then adjusted to pH 3.5 by adding 6N HCI The product was filtered, reslurried in 20 liters of water, filtered, reslurried in 20 liters of water, filtered, reslurried in 9 liters of distilled water, and filtered to a dry state.

The product had a nitrogen content of 0.19 percent and an isoelectric pH of 8.5.

EXAMPLE X The procedure was the same as in example lX except that the corn starch was slurried in 5 liters of water and diluted to 10 liters with water. The temperature was adjusted to 123 F. and 150 grams of Ca(OH) in one liter of water was added. Then 150 grams of 2-chloroethyldiethylamine hydrochloride in 200 cc. of water was stirred into the slurry. Thereafter 50 grams of sodium chloroacetate in 200 cc. of water was stirred in and after 18 hours at 120 to 124 F. the reaction was stopped by adding 460 cc. of 6N HCl which reduced the pH of the slurry from 10.9 to 3.5. The product was recovered as described in example 174.

The product had an isoelectric pH of 9.5, and an NCV viscosity at 0.10 AGU of 13 seconds.

EXAMPLE XI The procedure was the same as in example X except that the quantity of sodium chloroacetate was increased to 150 grams and the time of reaction was increased to 22 hours.

The product had an isoelectric point of 7.5 and an NCV viscosity at 0.15 AGU of 58 seconds.

The products of examples X and XI afforded good pigment retention in paper made from wood pulp fiber dispersions.

EXAMPLE xii 5000 grams of unmodified corn starch was slurried in 6 liters of water and diluted with water to 10 liters. 150 grams of sodium hydroxide and 500 grams of sodium chloride in 3 liters of water were cooled to room temperature and stirred into the slurry. The temperature of the slurry was raised to 1 10 F. and 150 grams of sodium chloroacetate in 500 cc. of water was stirred into the slurry and allowed to react for 48 hours at l25 F. One half of this slurry was adjusted to a pH of 3.5 with 6N HC 1 filtered, reslurried in i0 liters of water twice, then 5 liters of water, filtered and dried and labeled 3 l .5A-38.

To the other half of the slurry there was added grams of 4-chloro-Z-butenyltrimethyl ammonium chloride dissolved in cc. of water. The temperature of the slurry was raised to 124 F. and after a period of 24 hours reaction time at this temperature the reaction was stopped by adjusting the pH of 3.5 with 6N HCl and the product was recovered in the same manner as in the case of 3l.5A-38. The properties of the two products were determined as shown in the following table:

it will be observed that the unmodified corn starch was nonionic, the product labeled 31.5A-38 was anionic and the product labeled 31.5AB-38 was amphoteric and had an isoelectric pH of 4.3

EXAMPLE Xlll 5000 grams of No. 50 thin boiling corn starch was slurried in 5 liters of water, diluted with water to 10 liters and heated to F. 150 grams of calcium hydroxide in 1 liter of water was stirred into the mixture, the temperature rising to 1 10 F. 50 grams of sodium chloroacetate in 200 cc. of water was stirred into the slurry and was allowed to react for 23 hours at 123 F. At this point 1500 cc. of slurry was removed, the pH adjusted to 6.5 by adding 65 cc. of 6N HC l the solids filtered, reslurried in 2 liters of water, filtered, reslurried in 2 liters of water, filtered, reslurried in l liter of distilled water and the pH adjusted to 6.5, then filtered and dried and labeled 38.lA-38.

The remainder of the slurry was mixed with grams of 4- chlor-2-butenyltrimethylammonium chloride in 200 cc. of water and allowed to react at l20-l2l F. for 23 hours. At the end of this period the pH was adjusted to 3.5 with 339 cc. of 6N HCl The solids were then filtered, reslurried in 20 liters of water, filtered again, reslurried in 20 liters of water, filtered and reslurried in 9 liters of distilled water, the pH adjusted to 3.5 and then filtered and dried. This product was labeled 38. iAB-38.

A blank was also run by slurrying 1000 grams of No. 50 thin boiling corn starch in 2 liters of distilled water, filtering, reslurrying in 2 liters of distilled water, filtering, reslurrying in 2 liters of distilled water, and finally filtering and drying. This was labeled 38-Blank-38.

The product labeled 38.1A-38 was anionic. The blank labeled 38-Blank-38 was nonionic. The product labeled 38- lAB-38 was amphoteric and had an isoelectric pH of 8.7.

EXAMPLE XIV The procedure was the same as in example Xlll except that 50 grams of propane sultone was added to the slurry of thin boiling starch in water containing calcium hydroxide instead of the sodium chloroacetate. The propane sultone was allowed to react for 2i hours at 123 F. The 135 grams of 4-chloro-2- butenyltrimethyl ammonium chloride was stirred into the slurry and the reaction allowed to proceed for 24 hours at l20l22 F. The reaction was stopped by adding 3 l8 cc. of 6N HCl and the product was recovered in the manner previously described in example Xlll. This product contained 0.2 percent nitrogen on a dry basis. The initial temperature of gelatinization was 148. i F. and the isoelectric pH was 9.3

The invention provides new and useful amphoteric starches which can be employed for a wide variety of purposes. As previously indicated, these starches are characterized by containing both acid and basic groups which are substituted on IOIOIIZ one or more reactive positions of the starch molecule. The substitution of these groups reduces the gelatinization range of the starch. Unmodified corn starch gelatinizes at l43.6l 6 l .6 F. (62-72 C.). Granules of corn starch can be washed and freed of debris below about l43.6 F. (62 C.). The amount of substitution preferably for practical reasons should not reduce the gelatinization range below about ll8.4 F. (48 C.). For most practical purposes, therefore, the maximum amount of substitution will not exceed ten basic and acidic groups per lOO anhydroglucose units. In some cases, however, it may be desirable to have greater substitution (usually not more than 16) for preparing special types of products. In general, the ratio of acidic groups to basic groups is preferably within the range of 1:3 to 3:1, and a ratio in which basic groups predominate is usually best, preferably a ratio of basic to acidic groups of about 2:1.

It will be observed that in examples I to VII, the basic groups contain nitrogen in the form of an amine. ln example Vlll the basic nitrogen group is a cyanamide (NCN) group. in all of the examples the acidic groups are sulfonic acid or sulfonate groups or carboxylic or carboxylate groups but other types of acidic groups can be substituted.

While it is possible to carry out the reaction between the starch and the anionic and cationic etherifying reagents in the presence of an alkali metal hydroxide such as, for example, sodium hydroxide or potassium hydroxide, it is preferable to use an alkaline earth metal hydroxide such as, for example, calcium oxide, strontium hydroxide, or barium hydroxide, due to increased reaction efficiency. For example, in one series of reactions with the sultone, the reaction efficiency with sodium hydroxide was 24.6 percent, with calcium oxide 36 percent, with strontium hydroxide 32.8 percent, with barium hydroxide 31.3 percent, with magnesium oxide 10.9 percent, with potassium carbonate 6.3 percent, and with sodium carbonate 4.7 percent.

In the sizing of textile fibers a typical sizing composition can be prepared by mixing 100 pounds of an amphoteric starch prepared in accordance with this invention with 200 gallons of water, preferably with the addition of 5 pounds of petroleum wax. The thread or yarn to be sized, for example, a thread or yarn containing 65 percent polyester fiber (Dacron), and 35 percent cotton fibers, can be sized with this composition at 180 F. It will be recognized that at a temperature of 180 F., the amphoteric starch in the aqueous dispersion will be gelatinized.

In using this sizing composition, the number of yards of woven material between changes of loom stops can be increased. Afler weaving the sizing material can be removed by treatment with enzymes in the normal manner or by washing with a detergent water.

The compositions of the invention can also be employed in other uses, for example, in the finishing of textiles, in dyeing textiles and paper, in the sizing of paper, in the application of pigments or coatings to cloth and paper, as a coagulating agent in the separation of finely divided mineral particles from ores or water, in sedimentation, and for a wide variety of other purposes. A special use of amphoteric starches such as those described in the examples is addition to the wet end of a paper making machine of the Fourdrinier type to produce paper having enhanced resistance to ink penetration and enhanced oil resistance.

The term high amylose starch" when used herein refers to any starch or starch fraction containing at least about 50 percent by weight amylose. Exemplary thereof are Nepo| amylose (the amylose fraction of corn starch); Superlose (The amylose fraction of potato starch); Amylomaize or Amylon" (high amylosic corn starch with about 54 percent amylose); and Amylomaize Vlll (high amylose corn starch containing about 73.3 percent amylose). Amylomaize V"! with an amylose content of around 85 percent can also be used. The starch can be of any origin, for example, com,

wheat, potato, waxy corn, tapioca, sago or rice.

It will be apparent from the foregoing description that the cationic groups which are introduced into the starch molecule are amino radicals which are preferably tertiary amino groups or quaternary amino groups. The introduction of the anionic groups into the starch molecule can take place with the elimination of a hydrogen halide, for example, where sodium chloroacetate is employed the reaction occurs with the elimination of hydrogen chloride. in the case of propane sultone the reaction takes place with the opening of the sultone ring. In any case, the conditions used should be nongelatinizing with respect to the starch.

So much of the present application as relates to textile treatment with amphoteric starch is disclosed and claimed in my application Ser. No. [1,300, filed Feb. I3, 1970.

The invention is hereby claimed as follows:

1. An ungelatinized granular amphoteric starch having the formula wherein X is starch, An is an anionic group from the group consisting of carboxylic, carboxylate, sulfonic, and sulfonate. [phosphate and phosphonate,] Cat is a-cationic group from the group consisting of cyanamide, tertiary amino, tertiary amine salt, quaternary amino and quaternary amine salt, R and R, are divalent acyclic hydrocarbon or hydroxyhydrocarbon groups having one to six carbon atoms, m and n are each at least 0.5 per anhydroglucose units and the total of m+n does not exceed 16 per 100 anhydroglucose units.

2. A starch as claimed in claim 1 in which Art is carboxylic or carboxylate.

3. A starch as claimed in claim 1 in which Car is quaternary ammonium.

4. A starch as claimed in claim I in which Car is cyanamide.

5. A starch as claimed in claim 1 in which the ratio of mm is within the range of 1:3 to 3:1. v

6. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Cat is tertiary amino or tertiary amine salt.

7. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Car is quaternary ammonium or quaternary ammonium salt.

8. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Car is cyanamide.

9. An ungelatinized granular amphoteric starch having the formula v where X is starch, R and R', are divalent acyclic hydrocarbon or hydroxyhydrocarbon groups having one to six carbon atoms, R; and R are hydrocarbon having one to six carbon atoms,Z is v Y is hydrogen or a salt forming radical from the group consisting of sodium, potassium, calcium and ammonium, m and n are numerical values having a minimum of 0.5 per 100 anhydroglucose units, the total of m+n not exceeding l0 and the ratio of mm being within the range of l :3 to 3: l.

10. An ungelatinized granular amphoteric starch containing both cationic groups selected from the class consisting of cyanamide, tertiary amino, quaternary amino, tertiary amine salt and quaternary amine salt, and anionic groups selected from the class consisting of carboxylic, carboxylate, sulfonic and sulfonate, connected to the starch molecule through carbon' and oxygen, said cationic and anionic groups being sufficient in number to render said starch amphoteric but the total number not exceeding 16 per I00 anh'ydroglucose units.

11. An ungelatinized granular amphoteric starch as claimed in claim 10 in which the anionic groups are sulfonic acid.

12. An ungelatinized granular amphoteric starch as claimed in claim 10 in which the anionic groups are sulfonate.

13. An ungelatini ze d granular amphoteric starch having the formula where X is starch, R and R are alkylene, R and R, are hydrocarbon, Y is hydrogen or a salt forming radical and n and m are numerical values sufiicient to make said starch amphoteric but not exceeding a total of l6 per 100 AGU.

14. An ungelatinized granular amphoteric starch having the general formula i i i i i ag UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,622,563 Dated November 25. 1971 Inventofls) Lee H. Elizer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 9, "oycloalkphatic" should read oycloaliphatic line 2}, insert at the start of the line V Column 7, line 57, "1" should read 11 (second occurrence) Column 9, line '44. l"/ should read 4M2 Column 10, line 64, "The 135" should read Then 135 Column 11, line 71, "VIII" should read VII Column l2, line 18, the formula should read [An-R -O]g -X [O-R-Cat h line 22, delete [phosphate and phosphonate 1".

Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. A starch as claimed in claim 1 in which An is carboxylic or carboxylate.
 3. A starch as claimed in claim 1 in which Cat is quaternary ammonium.
 4. A starch as claimed in claim 1 in which Cat is cyanamide.
 5. A starch as claimed in claim 1 in which the ratio of m:n is within the range of 1:3 to 3:1.
 6. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Cat is tertiary amino or tertiary amine salt.
 7. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Cat is quaternary ammonium or quaternary ammonium salt.
 8. A starch as claimed in claim 1 in which An is sulfonic or sulfonate and Cat is cyanamide.
 9. An ungelatinized granular amphoteric starch having the formula where X is starch, R and R1 are divalent acyclic hydrocarbon or hydroxyhydrocarbon groups having one to six carbon atoms, R2 and R3 are hydrocarbon having one to six carbon atoms, Z is , Y is hydrogen or a salt forming radical from the group consisting of sodium, potassium, calcium and ammonium, m and n are numerical values having a minimum of 0.5 per 100 anhydroglucose units, the total of m+n not exceeding 10 and the ratio of m:n being within the range of 1:3 to 3:1.
 10. An ungelatinized granular amphoteric starch containing both cationic groups selected from the class consisting of cyanamide, tertiary amino, quaternary amino, tertiary amine salt and quaternary amine salt, and anionic groups selected from the class consisting of carboxylic, carboxylate, sulfonic and sulfonate, connected to the starch molecule through carbon and oxygen, said cationic and anionic groups being sufficient in number to render said starch amphoteric but the total number not exceeding 16 per 100 anhydroglucose units.
 11. An ungelatinized granular amphoteric starch as claimed in claim 10 in which the anionic groups are sulfonic acid.
 12. An ungelatinized granular amphoteric starch as claimed in claim 10 in which the anionic groups are sulfonate.
 13. An ungelatinized granular amphoteric starch having the formula where X is starch, R and R3 are alkylene, R1 and R2 are hydrocarbon, Y is hydrogen or a salt forming radical and n and m are numerical values sufficient to make said starch amphoteric but not exceeding a total of 16 per 100 AGU.
 14. An ungelatinized granular amphoteric starch having the general formula
 15. An amphoteric starch as claimed in claim 13 in which R is an ethylene radical, R1 and R2 are ethyl radicals, and R3 is a propylene radical, the ratio of m:n being within the range of 1:3 to 3:1. 